Argus
Cassandra
Charley
Jeremiah
admonisher
airplane spotter
cautioner
fire patrolman
fire warden
fireguard
flagman
forward observer
guard
lighthouse keeper
lookout
lookout man
monitor
night watchman
patrol
patroller
patrolman
picket
prophet of doom
roundsman
scout
sentinel
signaler
signalman
spotter
vedette
ward
warner
watch
watcher
watchkeeper
watchman
security guard
constable
corporal
driver
ensign
goblin
horseman
infantry
lancer
outpost
policeman
sailor
sergeant
trooper
warder
complementary
elementary
entry
gentry
supplementary